1. Field of the Invention
The field of the present invention relates to drive units for tarpaulin cover systems, particularly for, but not limited to, open-top vehicles (e.g. trucks).
2. Background
Open-top containers or vehicle bodies are often used to transport dry bulk materials, such as ores, coal, cereal, grains, wood chips, sand, gravel and stone. These types of containers or vehicles are much easier to load and unload because the upper portion of the container is open, i.e. not covered. Open-top containers or vehicle bodies provide many benefits, particularly, with respect to loading and unloading of materials. Nonetheless, using open-top containers—without any type of cover—can present several risks.
Most of the risks presented when using open-top containers or vehicle bodies without a cover results from weather and transport-related conditions. Excessive wind, heat, and/or cold can significantly damage loaded materials. Excessive moisture within a container, resulting from rain and snow, can also cause problems for many types of loaded materials (e.g. grain). Transport conditions are known to present problems when loaded materials are not covered. Vibrational and aerodynamic forces may cause portions of material to be carried away, resulting in contamination of railways, roadways, and waterways. Hazardous conditions may also result, especially when heavier loaded materials, such as gravel and stone, are blown or thrown off of open-top containers or vehicle bodies, during rigorous road conditions.
Because of these and other known problems, many open-top containers or vehicle bodies are now provided with tarpaulin cover systems. Tarpaulin cover systems protect loaded materials from exposure to cold, heat, wind, rain and prevent loaded materials from being carried away because of transport conditions. Sometimes tarpaulins cover systems use drive units that retract and extend a tarpaulin over an open-top container. These drive units, therefore, allow a user to manually or automatically cover and uncover loaded materials.
While known drive units are useful for their intended purpose, many have limitations. Some units are very complicated, heavy, and difficult to install. Other drive units are limited in that they can only attach to open-top containers (not limited to vehicles bodies) with two or more container walls. As a result, many drive units are not suitable for use with other types of open-top structures, e.g. beam and truss structures without walls.
For these reasons, among others, there is a clear need for improved tarpaulin cover systems and drive units for tarpaulin cover systems.